China has written a letter to U.N. Secretary General Kofi Annan, condemning Taiwan's latest bid to join the world body. China's government accuses Taiwan of bringing relations to what it describes as the "brink of danger." In a message to U.N. Secretary General Annan, China's envoy to the United Nations said Taiwan's government is "seriously threatening" peace and stability across the Taiwan Strait and the Asia-Pacific region.

Zhang Yishan says Taiwan is not qualified to participate in the United Nations, because it is a part of China.

China considers the self-governed island part of its territory, which should be eventually reunited with the mainland, by force if necessary. Beijing has previously indicated that it might consider adopting a law on what it calls "mandatory reunification."

Philip Yang is a political science professor at the National Taiwan University. He says Beijing fears Taiwanese President Chen Shui-bian will push for formal independence in his second term, which started in May. Mr. Chen's party supports independence, but Mr. Chen has been backing away from that position.

"They [Beijing] perceive that, after the inauguration speech of President Chen Shui-bian, nothing has improved," he said.

Analysts say a change in Taiwan's constitution, proposed by members of President Chen's party, could be seen by Beijing as a timetable for independence.

Beijing's opposition to Taiwan's U.N. bid coincides with its effort to block a proposed U.S. arms sale to Taiwan, which Beijing says would encourage separatist forces on the island. The United States does not have diplomatic relations with Taipei, but the government is mandated by law to defend the island if it is attacked.

Chinese Nationalist forces fled to Taiwan in 1949, during the Chinese civil war, establishing the Republic of China. It held a U.N. seat until 1971, when the General Assembly gave the seat to the communist government in Beijing.

Taiwan's U.N. bid has been backed by a handful of small nations that have diplomatic relations with the island.

Taiwan has been trying to regain its U.N. seat for more than a decade, but China and its allies have repeatedly blocked the proposal.

Mr. Yang says it has been growing harder for Taiwan to gain support for U.N. membership.

"Especially with the rise of the Chinese market, and also its political influence, I think small countries would probably change their minds gradually in the future about their support of Taiwan's bid for the United Nations," he said.

Meanwhile, Chinese state media reported that a U.S. citizen allegedly established what is called a "huge" Taiwanese spying network in the United States, as well as in China. David Dong Wei was arrested last September and is awaiting trial in China.